If water stops radiation and also keeps contained the fuel rods why donât we just build entire plantâs under water? Would a meltdown be much more survivable if it was under 20 feet of water? Oh what about underground reactors?
Edit: Thanks for the response so far :) But another issue is why not deep under ground such as in deep cave systems where a space has been created or in mountain where it can provide additional shielding? Basically why build it where they are built right now?
Comments
whatisnuclear ⢠4468 points ⢠2015-12-03
Advanced nuclear reactor designer here. Building nuclear power plants at sea is a very interesting idea, for several reasons:
- You can construct them in a shipyard, which is a controlled, repeatable environment with expert full-time employees who live nearby (not recently-trained temp workers living in a camp). Effectively, itâs an assembly line for huge power plants. This could conceivably bring construction costs and timelines down.
- Youâre intimately coupled to a infinite heat sink (the water). Turning nuclear chain reactions off is easy (just put the control rods in), but they still produce afterheat due to fission product decay and this must be cooled to prevent the release of radiation out of the fuel pins/containment into the environment (e.g. to prevent meltdown). If youâre sitting in the ocean, you can basically just open a valve and passively flood the heat transfer interfaces, keeping things cool without any external power. Thus, youâd be extremely safe.
- Youâre seismically decoupled from the ground, so you donât have to worry about earthquakes. âSure,â you might be thinking, âbut what about tsunamis?â No problem. Operate a few km offshore where the water is deep and you wonât even notice tsunamis going by (they have super-long wavelengths in deep water). Boom.
You DO have to worry about some new hazards, like ship collisions and huge storms. But shipbuilding is at a point these days that you can keep operating a major facility like the Prelude through a Category 5 cyclone, which is truly awesome. And you have issues like operation and maintenance will be more expensive. But you could just sail home to your shipyard-base to reload and do maintenance, which could actually be pretty slick.
You also worry about the fact that at sea, a leak somewhere is a leak everywhere, since the sea disperses things well. So even though itâd be much less likely to have a radioactive release, it would be a very big deal. This is a key PR challenge for floating nuclear. (Realistically, the retention and dilution of the radionuclides would be very good in the sea, but everyone can see that this technical fallback is completely societally unacceptable)
Lots of people are thinking about this. MIT is working on a floater. Russia has a one under construction to provide power to very remote villages. China is working on one. In the early 1970s, a company was formed called Offshore Power Systems that was going to build two huge nukes on barges off the New Jersey coast. It was cancelled after the oil crisis when the main demand (oil refineries along the coast) fell dramatically.
Personally, I think floating nuclear power plants (FNPPs) are one of humanityâs best options for transitioning away from fossil fuels rapidly, responsibly, and economically.
Anyway, great question!
(Also, of course, there are many naval reactors propelling ships and submarines all over, so the military definitely does build reactors on and in water. )